Electric power cable



c. a BEINNIETT swc'mxc Pom cum Filed lay 21, 1946 March 21, v1950 INVENTOR.

. Patented 31, 1950 ELECTRIC POWER CABLE Charles E. Bennett, Billgewood, N. 1., assignor to The Okonlte-Callender Cable Company, Incorporated, Paterson, N. 3., a corporation of New Jersey Application May 21, 1946, Serial No. 671,177

4 Claims. (Cl. 174-11) This invention relates to an improvement in electric power cable systems of the type wherein the insulated cable conductors are enclosed in a pipe line filled with insulating fluid which is maintained under superatmospheric pressure oi the order 01200 pounds per square inch.

In the type of cable system to which this invention relates a pump is located at each end of the system for maintaining the insulating medium under pressure, and my invention provides means for automatically sectionalizing th system, regardless of which pump is operating, should the pressure on the system drop below a predetermined value, due to a leak in the pipe line or bursting of the pipe line or other causes. thereby to prevent loss of a substantial amount of insulating fluid.

These cable systems are equipped at intervals with stop Joints, and in accordance with my invention a by-pass is provided around each of these Joints and equipped with valve mechanism of such construction that each by-pass will be shut oil upon a predetermined pressure drop in the system irrespective of which pump may have been operating to maintain the system under pressure. This will sectionalize the system and confine the loss of insulating fluid to the burst or leaking section between adJacent joints.

in the accompanying drawing Fig. l is a diagrammatic elevational view of an embodiment of the invention and Fig. 2 is an enlarged sectional elevational view of the valve mechanism.

Referring to thedrawings in detail, 2 designates the enclosing pipeline 01 'an electric power cable system of the type to which my inventlon relates.

This pipe line contains the insulated cable conductors of the system. these conductors being.

immersed in an insulating fluid such as insulat ing oil which is maintained under superatmospheric pressure either by the pumping station 4 at one end of the line, or pumping station 6 at the opposite end of the line.

The pipe line 2 is provided at intervals with stop Joints 6, each of which is by-passed b a I pipe Ill equipped with manually operated'shutoil valves l2 and with automatic valve mechanism l4, which is disposed intermediate the manual valves i2 and the construction of which isillustratedinFlg. 2.

The mechanism I4 is automatic in operation and is adapted to sectionalize the system at each joint I in the event the fluid pressure drops be. low a predetermined value and ir e p ctive 0! which of the pumping stations may have been employed to maintain the fluid under pressure.

Referring to Fig. 2, l8 designates the valve body which is threaded at each end for installation in the by-pass III. This valve body is provided interiorly with a diaphragm, web or wall I! which prevents the passage of insulating fluid through the valve body except through valve ports 20 and 22. These ports are controlled by oppositely seating valves 24 and 26, respectively.

Each valve structure comprises a bonnet 2B threaded to the exterior of the valve body It. The bonnet is capped with cap nut 30 upon which is threaded cap 32.

The valve stem, which is designated .34, is

24 and 26 are closed, and the pipe line between the joints 8 is filled'with insulating fluid in any convenient fashion. The valves springs 36 it will be understood, are set at the pressure at a which it is desired that the valves 24 and 26 shall close automatically. For example, if the fluid pressure to be maintained on the line is 200 pounds per square inch, the valve springs 38 might be set so that when the pressure drops to pounds per square inch the valves willclose.

After th line has been filled with 011 between joints, it will be apparent that if the pumping station 4 be started in operation the valves 24 and. nearest this station will remain closed until a pressure of the assumed minimum of 100 pounds per square inch has been built up in the line between this station and the nearest valve 24. The valve 24 will then open, the area oi its piston-like disc being sufficiently larger than that of the valve itself to produce a pressure difierential sufllcient to open the valve. 0n continued operation of the pumping plant the valves 24, the entire length of the system, will open successively, and as the valve bodies become filled and the pressure throughout the system exceeds the 100 pounds pressure for which the valves have been set, the valves 26 will open also. h Pumping station 4, it will be assumed, continues operation until the pressure in the system reaches 200 poundspersquare inch, at which The loading spring 3t time it will b apparent all of the valves 24 and 26 will be open, and while the pressure on the system will vary somewhat under normal operating conditions, it will not drop to the 100 pounds per square inch pressure for which the sectionalizing valves have been set, so that the valves 24 and 26 will remain open.

Let it be assumed now that a leak or burst oc curs in a section of the pipe line between a pair of joints 8, the section 46 for example. The operator at the pumping station 4 will note the increase in the operations of this station which being automatic in operation, will operate continuously instead of intermittently-its normal operation-in an endeavor to make up for the loss of insulating fluid escaping through the burst section. The operator shuts the pumping station down, so that the pressure in the system gradually lowers to the 100 pounds for which the valves have been set. Consequently the valves 24 and 26 will close automatically throughout the whole system, thereby sectionalizing the system at each by-pass, and the loss of insulating fluid will be confined to the section 46. Without the sectionalizing valves the entire system would be drained.

The same operation takes place if the pumping station 6, instead of 4 is employed for building up and maintaining pressure on the ystem, the only diilerence being that in operating the pumping station 6, the valves 26 rather than 24, open first on the initial building up of pressure on the system.

'It will be apparent from all of the foregoing that my invention provides a cable system of the type wherein the cable conductors are enclosed in a pipe line filled with insulating fluid which is placed and maintained under superatmospheric pressure by operation of either one of two pumping plants located at the ends of the system, means being provided whereby the line will antomatically be sectionaiized in the event of predetermined pressure drop in the system, thereby preventing excessive loss of insulating fluid, irrespective oi which pumping plant was employed to build up the pressure in the system.

It is to be understood that while I have described a specific embodiment of my invention, changes may be made in the details of construction and arrangement of parts within the purview of my invention.

What I claim is:

1. In combination an electric power cable system oi the type wherein the cable conductor is enclosed in a pipe line filled with insulating fluid, sectionalizing valves connected into the pipe line at intervals, pressure means connected to the pipe line at each end thereof, each of said pressure means being operative to maintain the insulating fluid under predetermined pressure, said sectionalizing valves being disposed in pairs and opening automatically upon the building up of pressure in the pipe line to the predetermined pressure by either of said pressure means, said valves closing automatically to sectionalize the system upon a predetermined pressure drop in the pipe line.

2. In combination an electric power cable system of the type wherein the cable conductorls enclosed in a pipe line filled with insulating fluid, joints at intervals along the line, by-possa around the joints, a pair of sectionalizing valve: in each by-pass, pressure means connected to each end of the pipe line, each of said pressure means being operative to maintain the insulating fluid under superatmospheric pressure, said sectionalizing valves opening automatically upon the building up of a predetermined pressure in the pipe line by either of said pressure means, said valves closing automatically to sectionalize the system upon a predeterminedpressure drop in the pipe line.

3. In combination an electric tem of the type comprising an insulated conductor enclosed in a pipe line containing an insulating fluid in which the conductor is submerged, stop joints at intervals along the pipe line, by-passes around the joints, a pair of oppositely opening sectionalizing valves in each bypass, pressure means connected to each end of the pipe line, each pressure means being operable to raise the pressure of the insulating fluid above atmospheric said sectionalizin valves opening when this pressure reaches a predetermined vahie under the operation of either of said pressure means and closing automatically to sectionalize the pipe line at each joint upon a predetermined drop in the insulating fluid pressure.

4. In combination an electric power cable system of the type comprising-an insulated eonductor enclosed in a pipe line containing an insulating fluid in which the conductor is subpower cable sysmerged, joints at intervals along the pipe line,

by-passes around the joints, a valve body in each by-pass provided with a partition extending across the same, the by-pass at one side of the valve body being connected into the body at one side of said partition while the by-pass at the other side of the body is connected thereto at the other side of said partition a pair oi ports through said partition or diaphragm, a valve for each port, said valves opening in opposite directions, pressure means connected to each end of the pipe line each of which is operable to raise the pressure of the insulating fluid above atmospheric, said valves opening when this pressure reaches a predetermined value under the operation of either or said pressure means, and loading springs for said valves for closing the same automatically to sectionalize the pipe line at each joint upon a predetermined drop in the insulating fluid pressure.

CHARLES E. BENNE'I'I.

REFERENCES CITED The following references are of record in the file of this patent:

Parker June 20, 1944 

